A bone fracture may be caused by single impact or torque, an accumulation of small stresses due to fatigue, overuse, repetitive activities, or medical conditions that weaken bones, such as bone cancer or osteoporosis. There are hundreds of thousands, if not millions, of bone fractures each year in the United States, and many more instances of bone fractures world-wide.
Bone fractures are generally treated by immobilization, where the fractured bone is reset into place and immobilized. Common approaches to immobilization include applying casts made of plaster or other material and/or placing the patient in traction. Additional methods of treatments include bone grafting and implantation.
When these treatment methods are employed, the patient is forced into a significant period of partial, or complete, inactivity, depending upon the nature and severity of the fracture. If a cast is used for immobilization, it will often be necessary to immobilize a large area of the body surrounding the fracture. While healing occurs, the muscles surrounding the fracture may atrophy from lack of movement and use, which adds to recovery time.
Bone grafting and implantation require one or more invasive surgical procedures, in which the patient undergoes local or general anesthesia. As with any surgical procedure, there is an increased risk of infection and the patient will also experience some discomfort during recovery. Rehabilitation will also be necessary, resulting in the patient spending additional time away from work or other activities.
Another concern when treating bone fractures is proper healing. In order to achieve optimal healing and recovery, the bone fragments should be completely reset and placed in the same alignment present before the fracture occurred. Depending upon the bone involved and the type of fracture, this may be difficult to achieve. In particular, it may be difficult to reset spiral fractures, compression fractures, and displaced fractures; further difficulty may be encountered in maintaining the bone fragments in proper position during healing and rehabilitation.
Thus, there is a need for a device that can be inserted into the medullary cavity of a fractured bone, and if necessary, to be removed in a manner that minimizes surgical invasion and the risk of further injury to the patient. There also exists a need for a device to adequately fill the medullary cavity and hold the bone fragments in proper alignment during healing and rehabilitation, and consequently there is a need to precisely position the device within the medullary cavity.